AB0591 ANALYSIS OF THE CLINICAL DIFFERENCES BETWEEN THE SUBTYPES OF GIANT CELL ARTERITIS.
Authors: M. D. C. Uyaguari Morocho, E. Fernández-Fernández, A. Ginon, I. Monjo, E. de Miguel
Journal: Annals of the Rheumatic Diseases (2022)

Background Giant cell arteritis GCA is the most frequent vasculitis over the age of 50. Nowadays, it is known that there are several subtypes of GCA depending on the vessels that are involved: cranial, extracranial and mixed. However, the clinical manifestations that differentiate these three subtypes have not been extensively examined until now. In the future, it is likely that the differential characteristics in the expression of the disease will be relevant in the prognosis and the follow up of these patients. Objectives The objective of the study is to investigate the clinical differences associated with these different patterns of GCA involvement. Methods This is a retrospective study of new consecutive patients diagnosed with GCA in our hospital for three years. All patients underwent color Doppler ultrasound of both cranial (superficial temporal arteries in the common superficial temporal artery and their frontal and parietal branches) and extracranial arteries (axillary, subclavian and carotid arteries) were explored. The ultrasound diagnosis was made according to the OMERACT definitions of the halo sign and a cut-off the intima media thickness of ≥0.34 mm for the branches of the temporal arteries ≥0.42 in the common superficial temporal artery and ≥ 1 mm for the axillary, subclavian, and carotid arteries was established. The clinical records of the patients were reviewed and their demographic, clinical and laboratory data were compared between the different patterns of ultrasound involvement of GCA. A p&lt; 0.05 was established as the limit of statistical significance. The EULAR recommendations of 2019 1 were used to establish the definitions of remission and relapse. The statistical analysis was performed using SPSS version 25. Results A total of 74 patients were included, 44(58.7%) women with a mean age of 78.6±8.6 years. Regarding the GCA subtypes, 18 (24.3%) patients had exclusive involvement of cranial giant cell arteritis CGCA, 12 (16.2%) patients had isolated involvement of extracranial giant cell arteritis LVGCA and 44 (59.5%) patients had mixed forms with cranial and extracranial MGCA. The characteristics of the population and of the GCA subtypes are shown in Table 1. Table 1. Clinical characteristics and GCA subtypes. Clinical characteristics Total GCA = 74 CGCA = 18 LVGCA = 12 MGCA = 44 CGCA vs. MGCA p CGCA vs LVGCA p LVGCA vs MGCA P Female sex, n (%) 44 (59.4) 10(55.5) 6 (50) 27 (61.3) 0.672 0.765 0.478 Age, mean ± S.D.years 78.6 ± 8.6 79.0 ± 8.1 73.2 ± 9.4 80.7 ± 7.9 0.505 0.031 0.077 ESR, (mm/h) mean S.D. 57.1 ± 35.5 66.1 ± 39.2 39.6 ± 24.5 56.6 ± 34.1 0.391 0.021 0.115 CRP (mg/dL) mean± S.D. 56.4 ± 57.1 50.1 ± 45.6 52.3 ± 52.5 60.7 ± 63.7 0.179 0.758 0.417 Constitutional symptoms, n (%) 59 (78.7) 12 (66.6) 12 (100) 35 (79.5) 0.282 0.025 0.087 Ischemic symptoms, n (%) 66 (82.66) 15 (83.3) 5 (41.6) 35 (79.5) 0.732 0.018 0.010 Remission for 6 months, n (%) 25 (33.3) 7 (38.8) 5 (41.6) 13 (29.5) 0.847 0.879 0.425 Glucocorticoid free remission, n (%) 8 (10.7) 1 (5.5) 2 (16.6) 5 (11.3) 0.475 0.320 0.622 Major relapse, n (%) 4 (5.3) 0 (0) 1 (8.3) 3 (6.8) 0.479 0.213 0.857 Minor relapse, n (%) 12 (16) 2(11.1) 3 (25) 8 (18.1) 0.492 0.317 0.598 GCA: giant cell arteritis; CGCA: Cranial giant cell arteritis; LVGCA: Large vessel giant cell arteritis; MGCA: Mixed giant cell arteritis; SD: standard deviation; p: value. The analysis of the results showed that patients with LVGCA are younger, have less ischemic symptoms and have lower ESR than patients with CGCA p&lt;0.05. Cranial involvement was associated with more ischemic symtoms than GCA with large vessel involvement, even in the mixed forms in which the cranial vessels are involved p&lt;0.05. Additionally, we observed a trend towards a higher percentage of present greater constitutional syndrome in the LVGCA group. The main limitation of the study is its low sample size when analyzing the subgroups, which does not allow confirming some of the trends observed in Table 1. Conclusion There are significant clinical phenotypic differences in the presentation of the different subtypes of vascular involvement in GCA. References [1]Hellmich B et al. Ann Rheum Dis. 2020 Jan;79(1):19-30. Disclosure of Interests None declared